How to modify payload response data in Spring application? - spring-boot

Question

I' m trying to add a random payload to the responses of a web service implemented with Spring Boot. My current approach is registering a ControllerAdvice component which modify the response body in the following manner:
#ControllerAdvice
public class PayloadInflater implements ResponseBodyAdvice {
protected Logger _logger = Logger.getLogger(PayloadInflater.class.getName());
#Value("${network.increased-payload:false}")
private boolean increasedPayload;
#Value("${network.payload-size:1000000}")
private int payloadSize;
#Override
public boolean supports(MethodParameter returnType, Class converterType) {
return increasedPayload;
}
#Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
byte[] randomData = new byte[payloadSize];
_logger.info("Generating random data programmatically");
new Random().nextBytes(randomData);
Map<String, Object> map = new HashMap<>();
map.put("payload", body);
map.put("benchmarkPayload", randomData);
return map;
}
}
Now the problem is that I've a frontend app also implemented in Spring Boot and using a RestTemplate and I'm not able to deserialize correctly the messages from the service.
org.springframework.http.converter.HttpMessageNotReadableException: Could not read document: Can not deserialize instance of java.lang.Boolean out of START_OBJECT token
at [Source: java.io.PushbackInputStream#36ac8a63; line: 1, column: 1]; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.lang.Boolean out of START_OBJECT token
at [Source: java.io.PushbackInputStream#36ac8a63; line: 1, column: 1]
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:240)
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.read(AbstractJackson2HttpMessageConverter.java:225)
at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:95)
at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:917)
at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:901)
at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:655)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:613)
at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:531)
at DeserializationTest.deserializationTest(DeserializationTest.java:52)
at DeserializationTest.deserializationTest(DeserializationTest.java:42)
at DeserializationTest.whenReadingBoolean_thenCorrect(DeserializationTest.java:33)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:252)
at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:141)
at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:112)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.apache.maven.surefire.util.ReflectionUtils.invokeMethodWithArray(ReflectionUtils.java:189)
at org.apache.maven.surefire.booter.ProviderFactory$ProviderProxy.invoke(ProviderFactory.java:165)
at org.apache.maven.surefire.booter.ProviderFactory.invokeProvider(ProviderFactory.java:85)
at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:115)
at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:75)
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.lang.Boolean out of START_OBJECT token
at [Source: java.io.PushbackInputStream#36ac8a63; line: 1, column: 1]
at com.fasterxml.jackson.databind.JsonMappingException.from(JsonMappingException.java:270)
at com.fasterxml.jackson.databind.DeserializationContext.reportMappingException(DeserializationContext.java:1234)
at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1122)
at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1075)
at com.fasterxml.jackson.databind.deser.std.StdDeserializer._parseBoolean(StdDeserializer.java:220)
at com.fasterxml.jackson.databind.deser.std.NumberDeserializers$BooleanDeserializer.deserialize(NumberDeserializers.java:178)
at com.fasterxml.jackson.databind.deser.std.NumberDeserializers$BooleanDeserializer.deserialize(NumberDeserializers.java:161)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:3798)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2922)
at org.springframework.http.converter.json.AbstractJackson2HttpMessageConverter.readJavaType(AbstractJackson2HttpMessageConverter.java:237)
... 45 more
this is an example of the body data get from the service:
{
"payload": true,
"benchmarkPayload": "this is a random string"
}